The city wants to renew its fledging residential permit parking system for at least another two years.

A bill sponsored by Assembly members Patricia Fahy and John McDonald and state Sen. Neil Breslin would boost the program's pilot period from two to four years to allow more time to assess whether the 15-month-old system is working.

The renewal push comes as enrollment numbers so far appear to have dropped significantly in the second year, with the number of permits sold through March in every permit zone down by at least half.

Fahy, an Albany Democrat, said she would like to see the system made permanent as in other cities, including Rensselaer, but views the two-year extension as a more likely compromise with the end of the legislative session swiftly approaching next month.

"To me, this is another one of those fairness issues," Fahy said. "So we're pushing hard to get it by the end of the session."

If the bill doesn't pass by next month, the Legislature isn't expected to be back in the Capitol until January — about a month before the pilot program expires Feb. 15.

"If you don't do it in June, you're in effect left hanging until January of next year," said Common Councilman Richard Conti, who represents most of the largest permit zone around Center Square.

The legislation finally passed the Legislature in 2010 after more than two decades of tug-of-war between local officials eager to resolve the downtown parking crunch and state workers unions that opposed it. One of the major concessions was a two-year sunset period. After several years of logistical ramp-up, the system went live on Feb. 15, 2013.

It also passed the Senate in the two-year window in which Democrats — including Breslin — controlled the upper chamber, which is now run by Republicans and breakaway Democrats.

Broadly, the system restricts long-term parking in about 2,750 spaces on residential blocks within three-quarters of a mile of the Empire State Plaza to permit-holding residents. Visitors are still allowed to park on the blocks for up to two hours at a time when the system is in effect on weekdays between 8 a.m. and 6 p.m.

Jackie Ring, president of the Center Square Association, said the permits have worked as planned on some blocks, but on others closer to the Plaza, like lower State and Chestnut streets, some people appear willing to risk getting tickets.

"We'd like very much to see it extended," Ring said. "Our observation has been that on some blocks, it really has had a major impact."

Ring said abuse of visitor passes is still a problem. And the city's attempt to rein in abuse by selling the passes separately for $5 may have contributed to the decline in the overall number of permits sold.

Through March, for example, the number of overall permits sold in Zone A around Center Square dropped from about 5,300 last year to about 2,600 this year, City Clerk Nala Woodard said. The other two zones saw similar or larger declines.

"I can't draw any conclusions as to why the permit sales are down," Woodard said, noting all permit holders were sent renewal notices by the city. Conti said it may just better reflect the actual demand.

Both unions fought the legislation in the past because their members without assigned garage spaces downtown were often the ones using free on-street parking to the annoyance of downtown residents.

PEF President Susan Kent said her union's efforts are focused on reaching a new understanding with the Office of General Services to ensure the agency divides up existing state-controlled parking spaces fairly among employees.

"What we want to do is ensure there's a fair and equitable process for people to vie for spots in the parking lots," Kent said. "Our focus was never against the residents."

Therese Assalian, a spokeswomen for the CSEA region that includes Albany, said some members have been inconvenienced by the restrictions but that the union's attention lately has been on those who have had their offices shuffled amid the Cuomo administration's so-called re-stacking of state agencies.

"Our focus has shifted to members that are being relocated," Assalian said.

Mayor Kathy Sheehan, who helped implement the permit system as city treasurer, is also behind the renewal effort.

"We hope to see it done," Sheehan's chief of staff, Matthew Peter, said.